1) The critical crack length for a through crack in a thick plate of 7150-T651 aluminum alloy that is in uniaxial tension. For this alloy Kic = 25.5 MPa SqRt.(m) and sigma f = 400 MPa. Assume Y = SqRt. (pi)
2) What is the largets size (mm) internal through crack that a thick plate of aluminum alloy 7075-T651 can support at an applied stress of (a) three-quarters of the yield strength and (b) one-half of the yield strength? Assume Y=1